I-140 approved!?

Hi everyone,
I accidentally logged in to USCIS' website just last night to verify my friend's denial of her petition. I was prompted to check my own case also and I was so surprised to see this:

Receipt Number: SRCXXXXXXXXXX
Application Type: I140, IMMIGRANT PETITION FOR ALIEN WORKER
Current Status: Approval notice sent.
On January XX, 2009, we mailed you a notice that we have approved this I140 IMMIGRANT PETITION FOR ALIEN WORKER. Please follow any instructions on the notice. If you move before you receive the notice, call customer service.

My question is, why did I not receive an e-mail from the USCIS to notify me of the approval, nor did I get any correspondence from my agency? Had I not logged in to USCIS website accidentally, I wouldn't have the slightest thought that my case has been approved. And when I checked the processing dates of Texas Service Center, they are 8 months behind. Current processing is still Aug. 2007. My receipt notice, which happens to be my priority date is April 2008. What do I do now? It has been 2 months since my case was approved. I know I have to call my agency, however, it is weekend so meantime, I am seeking the advise of everyone who can share his/her thoughts. Can Ms. Suzanne or Silverdragon enlighten me please? Thank you very much!